After last year's semi-washout, will again try to draw out exploits of Chrome OS at March security conference

Google yesterday said it would again host its Pwnium hacking contest at a Canadian security conference in March, putting $2.7 million at stake to draw out researchers who can hack its browser-based operating system, Chrome OS.

Dubbed Pwnium 4, the challenge will again pit researchers against Chrome OS, but this year will let them choose between Intel- or ARM-powered laptops. In 2013, hackers had to try to crack a Chromebook with an Intel processor.

Prizes of $110,000 and $150,000 will again be rewarded to individuals or teams who can hack the operating system, with the top dollar handed to those who deliver an exploit able to persistently compromise an HP or Acer Chromebook -- in other words, hijack the device so that it remains under their control even after a reboot.

Google capped the total up for grabs at $2.71828 million, giving multiple researchers a chance at prize money. The "2.71828" comes from a mathematical constant that is the base of the natural logarithm.

Last year Google put $3.14159 million in the pot -- another nod to mathematics, as those are the first six digits of the value of Pi -- but paid out just $40,000 to a prolific hacker who goes by "Pinkie Pie," the contest's sole participant, for what Google later called a partial exploit.

Google also said it would consider larger bonuses this year to researchers who demonstrated what it called a "particularly impressive or surprising exploit," such as one that could circumvent kASLR, (kernel Address Space Layout Randomization), a relatively new variant of the better-known ASLR anti-exploit technology used by Apple's iOS and OS X, Microsoft's Windows 8 and Chrome OS.

Even with bonuses in play, it's unlikely that Google will end up spending anywhere close to $2.7 million this year.

To qualify for the prizes or bonuses, winners must provide functional exploit code and details on all the vulnerabilities put into play, as was the case last year.

Pwnium 4 will take place March 12 at CanSecWest, the Vancouver, British Columbia, security conference known for another hacking contest, Pwn2Own, which last year was co-sponsored by HP's Zero Day Initiative (ZDI) bug bounty program and Google. HP has not yet announced the details of its 2014 challenge.